CHARACTERISTICS OF ELECTRIC FIELD AND WAVE SIGNATURES

MEASURED BY THE CLUSTER SATELLITES DURING

MAGNETOPAUSE CROSSINGS

R.Behlke (1), M.Andre (1), A.Pedersen (2), H.Opgenoorth (1,3), P. Eglitis (1)

(1)IRF Uppsala,SE-75591 Uppsala,Sweden,(2)University of

Oslo,Norway,(3)Finnish Meteorological Institute,Helsinki,Finland

The typical signatures of magnetopause crossings by high altitude satellites are

relatively well understood stepfunctions in the magnetic field strength and

direction, and more gradual changes of various plasma populations, indicating

diffusion processes through the magnetopause into the so-called boundary layer.

The electric field behaviour and characteristics of different wave modes in this

region are less well understood, but certain broad band wave phenomena seem to be

present at all times and locations just inside the magnetopause. We will present

initial Cluster studies of the characteristic behaviour of the electric field at the

boundary and associated observations of waves and solitary structures. Whenever

possible we will try to establish a more global view of the general state of

magnetospheric disturbance level, and solar wind activity inpinging on the

magnetopause, using data from the global network of ground-based instrumentation

and satellites in the solar wind.